Iron for Hair Growth

Iron is one of the few nutrients with a real, defensible link to hair growth - but only through one route: fixing a deficiency that was causing hair to fall out in the first place.

Low iron stores push hair follicles out of their growth phase prematurely, producing the diffuse shedding known as telogen effluvium. Repletion allows follicles to resume normal cycling, and over six to twelve months the hair that was being lost grows back. That is regrowth of what you were losing, not new growth beyond your baseline. Iron is not a growth stimulant, and in people with normal iron stores it does nothing for hair while adding overload risk. Testing before treating is the whole ballgame here.

The hair matrix contains some of the most rapidly proliferating cells in the body, and iron is essential to ribonucleotide reductase, the rate-limiting enzyme in DNA synthesis. When iron is short, the body prioritises red cell production and vital organs, and follicles lose out early.

Deprived follicles shorten their anagen growth phase and shift into telogen. Because telogen lasts around three months before the hair is shed, the visible loss appears two to three months after the deficiency began - and regrowth is similarly delayed after correction. Gene expression studies have identified iron-regulated genes within the hair follicle itself, suggesting a local role rather than a purely systemic oxygen-delivery effect. Ferritin appears to be the most sensitive marker, which is why it is checked in hair loss even when haemoglobin is normal.

Hair-focused dermatology usually targets a higher ferritin than the threshold for treating anaemia, and treatment runs long.

There are currently no studies linked to this pairing in our library, so no study list is shown.

The observational literature consistently finds lower ferritin among women with telogen effluvium and diffuse hair loss than in matched controls, and iron studies are a routine part of the dermatological workup for that reason. Clinical experience supports resolution once stores are rebuilt. The evidence is weaker than its popularity implies. Randomised trials are scarce, the ferritin thresholds quoted for hair vary widely between sources, ferritin rises with inflammation independent of iron stores, and several studies have found no association at all. The claim that survives scrutiny is narrow: correcting deficiency stops deficiency-driven loss.

Constipation, nausea, cramping and dark stools are common with oral iron, and adherence across six to twelve months is the practical hurdle. Alternate-day bisglycinate is generally the best-tolerated approach.

Many causes of hair loss are unrelated to iron: thyroid disease, androgenetic alopecia, alopecia areata, PCOS, postpartum hormonal shifts, crash dieting, medications and scarring alopecias. Patchy loss, scalp inflammation, visible scarring or hair loss with systemic symptoms should be assessed by a dermatologist rather than self-treated.

Absorption interactions matter more than usual here because the treatment course is long.

No studies are currently linked to this pairing, so no reference list is available. This section will populate as evidence is added to the library.